Wet, Cold Soils May Result in Diseases this Spring

3/13/2019

The 2019 crop season looks to be getting off to a cold, wet start. The abnormally cold winter has resulted in exceptionally cool soil temperatures and deep frost. Sioux Falls recently set a record for the most consecutive days below freezing ending in March at 33 days. This gets us all thinking about how our planting conditions may be.

The likely soil conditions we will have to deal with greatly increases the importance of combating seedling diseases in our soybeans. The wet 2018 harvest weather throughout the Midwest created issues with some soybean seed varieties and quality for 2019. Most companies will have some varieties that are at 80-85% germ bean seed (90% is normal). In some cases, Diaporthe/Phomopsis fungus infecting the seed was generally to blame. Discuss with your local Agronomist about your seed placement for this spring.

Phomopsis Infected Soybeans

This weakened seed will make it even more important this spring to have fungicide seed treatment on your seed. We have reseach to show this protection to start your season off strong. Below shows 2018 seed treatment vs. untreated seed germination data.

U of Minnesota & Independent Sources

Conditions that result in some key diseases are shown below. Many conditions favor wet soils which we most likely will experience at the start of this 2019 season. Some diseases shown below favor cooler and/or warmer soil conditions. Keep this in mind if you are planning later soybean planting dates; we still recommend seed treatments for this protection to optimize germination.

Lastly, another watch-out we may have in 2019 from our saturated soils from last summer-fall and our potential for saturation this spring, is how much of our beneficial nitrogen-fixing bacteria we will have. Most microbial populations need ample oxygen in the soil to flourish. Soybeans need these nitrogen-fixing bacteria to create the needed nitrogen for grain-fill. CFE has tested Preside CL inoculant ($3.75/unit cost) in our replicated trials the last 2 years (6 sites) and we have gained an average of 1 bu/ac yield bump. We suspect inoculants will be more important than normal this year with our anaerobic soil conditions that likely killed many of the existing populations.